As the listener to a series of stories about electric fences, let me
assure you, they do hurt when peed on! My grandfather did it once, and
for the rest of his life, he'd pass down the family wisdom (just about
the time he opened his third beer) "Boy, don't ever piss on an electric
fence", he would tell me. It made quite an impression on him, and I
think from that point forward his interest in women was purely
gallant--but that may have been because of the heart problems...
The third rail is rather impressive. At 600 volts, DC, and who knows how
many amps (thousands?) it is dangerous. I worked on the 4th Avenue
subway reconstruction in Brooklyn in the late eighties, and we would
light the tunnels with five 120V lamps in series, mounted on a paddle,
with insulated leads and huge alligator clips. We always placed the
return before hooking to the live rail, and you could see a spark jump
as contact was made. I remember about that same time a motorman was
electrocuted when he came down out of the train in a flooded section of
track. We paid a lot of attention to it, and were very respectful.
People do a lot of urinating in the subway tunnels, but not on the third
rail!
You do get an arc across a single opening, but I don't think you would
get an arc at medium voltages across multiple openings in the circuit or
flow. Of course at high voltages, we get incredible arcs--across wide
spaces and multiple streams--like lightning, for instance. The crucial
question would be "what voltage"? Once established, an arc will continue
until such time as the space becomes too long to jump. That's the
principle we utilize for electric welding. We strike the arc, and then
back off slightly to create the proper conditions for the transfer of
metal--although the rod held to the same welding position before an arc
is struck will not create the "arc-over". To a certain point,
lengthening the arc increases the heat, at least to my untrained eye.
As to the original question about the electric fence, a flow is needed,
but it only need be a steady stream between the fence and the sensitive
parts <gr>.
Mike Wood, Cincinnati
Stephen A. Lawrence wrote:
Frederick Sparber wrote:
Reminiscent of the early 1940's when a neighbor kid urinated on
an electric fence,Once.
My first thought on reading this was "Ouch!!". It reminds me of a
tale I heard of a drunk taking a leak on the third rail of the subway,
for an even bigger "ouch".
But my second thought was, "How can this work??? Something's weird
here!"
I'm sure we all know what a stream of urine looks like -- sparkly, not
smooth. And I expect we all know why: like the ubiquitous displays in
science museums of a stream of falling water with a strobe light
flashing on it, which "freezes" the stream as a line of little beads
when the strobe's set just right, the stream breaks up into droplets
very early -- long before it would actually hit anything.
So, at the point of contact with the wire, the "stream" is actually a
line of separate falling drops. It's not a continuous stream, at all.
But for these tales to be true, the "stream" must conduct electricity.
How can a line of disjoint drops conduct electricity?
Are these stories of disastrous encounters with electric fences and
third rails all apocryphal, or is there some mechanism by which
current can flow through a discontiguous line of water droplets?
Fred
----- Original Message -----
*From:* Frederick Sparber <mailto:[EMAIL PROTECTED]>
*To: *vortex-l <mailto:vortex-l@eskimo.com>
*Sent:* 12/17/2005 5:52:07 AM
*Subject:* Re: A Conductive Jet Switch?
Since exploding wire technology is employed to maximize energy
density, but
is slow and cumbersome, why not a jet of electrolyte or metal to
effect kilojoule-megajoule
energy discharge of capacitor banks?
For instance a pool of Lithium Hydroxide Electrolyte, D2 Gas, or
D2O on top of a Cathode Pool of
Mercury with an insulation-sleeved Tungsten-Tipped Anode in a sealed
chamber, triggered by
electro-hydraulic actuation of a plunger-orifice device in the
pool?
Fred
